Think I'd walk away unless it was cheap. No adjustment that I know of and repair entails splitting the tractor. I believe the main shift is synchromesh but the range shift isn't. Sound to me like some gear jamming was going on. Unless you have a facility to spit it, I'd pass. That is big stuff and you need the proper equipment to split it and depending on hours, you'll most likely need to renew the clutch, pressure plate and associated parts too. I purposely stayed away from a DT model when I bought mine. The hydraulic shuttle is a bit more expensive but no dry clutch to deal with other than a damper plate that lasts forever.